/**                                                                                                                                                                                
 * Copyright (c) 2010 Yahoo! Inc. All rights reserved.                                                                                                                             
 *                                                                                                                                                                                 
 * Licensed under the Apache License, Version 2.0 (the "License"); you                                                                                                             
 * may not use this file except in compliance with the License. You                                                                                                                
 * may obtain a copy of the License at                                                                                                                                             
 *                                                                                                                                                                                 
 * http://www.apache.org/licenses/LICENSE-2.0                                                                                                                                      
 *                                                                                                                                                                                 
 * Unless required by applicable law or agreed to in writing, software                                                                                                             
 * distributed under the License is distributed on an "AS IS" BASIS,                                                                                                               
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or                                                                                                                 
 * implied. See the License for the specific language governing                                                                                                                    
 * permissions and limitations under the License. See accompanying                                                                                                                 
 * LICENSE file.                                                                                                                                                                   
 */

package algorithms.kiwi.util;

/**
 * A generator that is capable of generating ints as well as strings
 * 
 * @author cooperb
 *
 */
public abstract class IntegerGenerator extends Generator 
{
	int lastint;
	
	/**
	 * Set the last value generated. IntegerGenerator subclasses must use this call
	 * to properly set the last string value, or the lastString() and lastInt() calls won't work.
	 */
	protected void setLastInt(int last)
	{
		lastint=last;
	}
	
	/**
	 * Return the next value as an int. When overriding this method, be sure to call setLastString() properly, or the lastString() call won't work.
	 */
	public abstract int nextInt();

	public abstract Pair<Integer, Integer> nextInterval();
	
	/**
	 * Generate the next string in the distribution.
	 */
	public String nextString()
	{
		return ""+nextInt();
	}

	/**
	 * Return the previous string generated by the distribution; e.g., returned from the last nextString() call.
	 * Calling lastString() should not advance the distribution or have any side effects. If nextString() has not yet
	 * been called, lastString() should return something reasonable.
	 */
	@Override
	public String lastString()
	{
		return ""+lastInt();
	}

	/**
	 * Return the previous int generated by the distribution. This call is unique to IntegerGenerator subclasses, and assumes
	 * IntegerGenerator subclasses always return ints for nextInt() (e.g. not arbitrary strings).
	 */
	public int lastInt()
	{
		return lastint;
	}
	/**
	 * Return the expected value (mean) of the values this generator will return.
	 */
	public abstract double mean();
}
